Looking for a first handgun...

[Pointshoot]

For general field use I'd go with a revolver. A 357/38 is very versatile. The muzzle blast (noise) level with 357 is very high, you'll want to have hearing protection in when using it. This is less of a concern with lower pressure rounds such as the 38 Special if required to shoot in a quick emergency. Of course, always use hearing protection when you can do so.
Power levels that can be attained and the variety of available bullet shapes make the 357/38 a good choice in a field revolver. There are advantages to semi auto pistols for defensive use (higher capacity), but in my opinion this is greatly reduced by the fact that you can't use hollow points in your country. 9mm full metal jacket bullets aren't great defensive performers. I'd rather have the big power advantage that you get in a 357/38 Special revolver. You can use round nose, semi wadcutter, or full wadcutter bullets in it.

If it works for you, bigger caliber chamberings have their advantages. A 44 magnum offers considerably extra power and you can shoot lower pressure 44 Specials. The 45 Colt (LC not ACP version) is a great round too. Brian Pearce, a gun writer based in the American west has carried a 45 Colt revolver on his hip while on horseback since he was your age (or younger). He worked on his family's cattle ranch and also hunts. He has pointed out a big advantage of using a lower pressure round such as the 44 Special & 45 Colt. If called upon to actually shoot, the lower muzzle blast is much better for your hearing. (The 38 Special is also a low pressure round.) Sometimes when doing other things in the field or on horseback a situation can quickly arise where you aren't able to put your hearing protection in first, before taking a shot.

Of course, these various options may or may not be readily available where you live, so you'll have to choose accordingly.
Your English is excellent. I'm just starting out learning Spanish and I would be very pleased to have your level of foreign language proficiency. Good luck in your choice and have fun !

 

[ArchAngelCD]

You should not limit your handgun choice because you will be riding horseback on the ranch. All you need to do is buy the proper holster and any handgun will be safe from falling off your body. There is no need to have the gun unloaded while you ride either.

I'm a revolver fan and they work very well for ranch duty. Since you said S&W handguns are available and 38/357 ammo is available that's what I would buy. A S&W M686 or M686+ w/4" barrel.

A holster like this one will keep your gun secure but accessible and it's comfortable.
http://www.desantisholster.com/DUAL-ANGLE-HUNTER

I hope that helps a little...

 

[Manny]

Two great choices IME, but for use in the field I'd think your most useful choice would be a .357 revolver. Especially given that you have restrictions on what ammo that is legal, the .357 gives the most useful options. Should you need to deal with problematic cattle, a hardcast bullet would work quite well to solve the problem. Lighter .38 Special power loads would be great for lesser game of targets. As big a fan as I am of the 9mm, for the work the OP might have in his described circumstance I think a .357 would be a better choice.

 

[TreeDoc]

Ruger Blackhawk or New Vaquero 357. 5 1/2 barrel or 4 5/8. If you are riding a horse and may see a time when you may actually have to fire from the saddle, a single action is the only way to go. As you may already know, firing a gun, any gun from atop a horse is a tricky deal. It's not like movies, unless your animal is really trained well. When you squeeze off that shot, the horse is going to move, I guarantee that. There lies the problem with the auto or double action revolver. Your finger is on the trigger as the horse rears, bucks, turns, backs a whole host of movements.
In that moment following the shot and controlling the horse are you able to take your finger off the trigger; or are you more concerned with control of the horse as to not fall
off? Most are more concerned with the horse at that moment not the gun.
And yes, horses have been shot and riders have shot themselves from this very thing. Want to shoot a hog? Carry 1 of those 10 rifles in the scabbard.

 

[tomrkba]

About the revolver, I thought about a .44 mag at first because I hunt wild boar occasionally, but I'm not sure about the recoil. I'm big for my age, 6ft tall and I weigh 154 pounds, but I'm not sure if that matters.

The good news is that a gun chambered in 44 Magnum can fire 44 Special. If you can reload, you get three levels of 44 Magnum, as described by Patrick Sweeney in "Reloading the .44 Magnum".

I have had bad luck with CZ75B pistols. If you can try it before buying it, do so.

 

[BCRider]

You have not really said what this gun will be used for. A carry gun on the ranch? For competition? Just for fun target shooting? Or, more likely, some combination of all these?

For a range only working gun to use for pest control on the ranch there's something to be said for the basic single action six shooter. Especially today's guns that commonly have a transfer bar action so you can safely carry with all six chambers loaded. But ranch use and for plinking that is just about where their usefulness ends. (and I'm a big fan of single actions).

For a mix of competition and ranch use a double action or semi auto would work well. In the case of that CZ I would suggest you carry it in the loaded chamber with hammer lowered condition. This makes the gun that much safer to carry as you don't need to worry about the safety being accidentally switched to "FIRE". Then for use against varmints or for mercy kills on any cattle that have gotten hurt beyond saving you can either shoot the shot in double action or simply cock the hammer back and shoot it in single action mode.

As far as noise and calibers go I would heartily go with the others that say any magnum round will make your ears ring for the rest of the day if you ever need to use it without hearing protection. And anything that makes your ears ring like that has done some long term damage. The good news though is that if you got a .44Mag revolver you can shoot .44Special loads from it. These can either be actual factory .44Spl or if you and your dad reload your own then you can go with .44Spl loads in .44Mag casings. Special loads will still make you jump from the noise if you have to shoot without plugs or ear muffs. But at least they won't leave you wondering who is ringing the bells off in the distance for the rest of the day.

And due to the heavier bullet used in a .44Spl the hitting power can be up there with a .357Mag bullet for effectiveness against cattle or varmint animals.

Again, so much depends on the use of this gun.

As mentioned your English is very good. And we're more than happy to aid you in getting some extra practice....